Recently, residential houses have been designed to be well insulated and air-tightened for meeting energy conservation requirements. The purpose of this study is to evaluate the energy consumption and thermal comfort of the floor heating and the forced air heating systems for several thermal insulation levels using a thermal manikin and CFD calculation. CFD calculations are performed for a room that models the experimental room where the thermal manikin experiments were conducted. From the results of the experiments and CFD calculations, it is found that the heat input of the floor heating system is smaller than that of the forced air system. The heat input of the forced air system tends to approach that of the floor heating system when the thermal insulation is improved.